Core drill construction



Dec. 22,' 1931. F. c. MERRITT 1,837,469

l i conE DRI'LL cnNs'rRuc'rIoN Filed sept. e, 1927 Patented Dec. 22,19.31

UNITED STATES PATENT OFFICE FLOYD C. MERRITT, F LOS ANGELES,CALIFORNIA,ASSIGNOR TO ELLIOTT DRILL- ING COMPANY, A. CORPORATION OF CALIFORNIAGORE DRILL CONSTRUCTION Application iled` September 6, 1927. Serial No.217,689.

My invention relates to the art of making cores in oil wells, being moreparticularly a core drill of the double barrel type, in which a flushingHuid is utilized during the drilling operation. Various.l types of coredrills have been produced which are ordinarily satisfactory inmost typesof formation encountered, but insome instances, such as when what isknown to the trade as a cemented conglomerate is encountered, whichcontains quartz, pebbles and other hard substances, the drills nowcommonly used have a tendency to spin during the drilling operation andin view of the fact that-ordinarily the fiushing Huid is not carriedsufficiently close to the cutting level, the teeth of such drills burnand fuse, thereby destroying the efficiency of the drill.

The principal object of my invention is to produce a core drill of theclass described of simple form and construction in which a plurality ofblades are used for the cutting operation and in which the flushing iuidis brought very close to the cutting level and in close proximity to theforward face of the blades. Other objects and advantages will appea`hereinafter from the following description and drawings.

Referring to the drawings, which are for illustrative purposes only,

Fig. .1 is an elevation, partly in section, showing a drill embodyingaform of my invention.

taken at a90 angle to that shown in Fig.l 1, and

Fig. 3 is a sectional plan view on line 3-3 of Fig. .2.

The drill consists of a cutter head 11 interiorly threaded at its upperend to receive a tool joint 12, the outer barrel of the drill indicatedat 13 being threaded to the up per end of the tool joint. The head 11consist's of a hollow body havinga iuid receiving recess 14. The lowerend of the head is provided with dove tail slots 15 as shown in Fig. 3,converging inwardly to a central opening 16 formed in the head, suchopening 16 terminating in a core receiving opening 17 at its Fig. 2 isan elevation, partly ink section,-

lower end, such core receiving opening being of smaller diameter thanthe openlng 16, thereby forming a shoulder 18. Mounted in the slots 15are four cutting blades 20 and 21, the cutting blades 20` being ofsubstantially the same diameter as the head 11, and the cutting blades21 extending outwardly therefrom to cut a hole of larger diameter thanthe head.. These blades 20 and 21 are inserted in the head from theinside and, when in place, are held in ixed relationto the head by meansof a sleeve 25 seated on the shoulder 18, the upper end of the sleeve 25being engaged by the lower end of an inner barrel 26, which is threadedint'o the opening 16 in the head.

It is to be understood that the sleeve y25 engages the inner face oftheblades 2O and 21, thereby holding the same outwardly in the dove tailslots 15, the blades being similarly shaped to t such slots.

It is to be understood that the upper end of,

the inner barrel 26 is provided with a valve, not shown, as isordinarily done in this class of drills, the upper end of the outerbarrel 13 being connected to the drilling string, not

shown.

Attention is called to the fact that the cutting edges 30 of the blades20 extend below the lower end of the head 11, and the cutting edges 31of the blades 21 lie in a plane sub stantially above the plane oftheedges 30, as shown in Fig. 2, such lower end of the head being'roundedofl" as indicated at 32. The.

head is provided with fluid-discharge passages 33 connecting with therecess 14.-, which receives the Huid from an annular-passage 34 formedbetween the inner and outer barrels. The fluid passages 33 terminate attheir lower ends in outlet openings 35 which are arranged adjacent totheforward face of the respective blades, as indicated Jin dotted lines at36 in Fig. 3, such outlet openings 35 being also in the lower roundedend of the head, so that the fluid discharged is directly on the forwardface of the blades and adjacent to the cutting edge of the same, itbeing understood that the drill rotates in the direction of the arrowshown in Fig. 3.

If desired, a core catcher may be'used, con- 5 25 above the corecatcher38. The core catcher 38 in the form shown is provided with a series ofspring fingers 40, secured at their lower ends in any suitable manner tothe core catcher and extending inwardly at their upper ends, as shown inFig. 1.

I claim as my invention:

1. In a core drill, a cutter head having a core receiving opening withan inwardly extending shoulder and a fluid receiving recess therein, aplurality of cutting blades mounted on said head having their cuttingedges arranged at different cutting levels, means for holding saidblades on said head comprising a removable sleeve resting on saidshoulder, and fluid discharge passages for said recess having dischargeoutlets located between said blades at different levels.

2. In a core drill, a cutter head having a plurality of dove tailedslots formed in the through, cutting blades in said slots extendingoutwardly from said head, said head having a central longitudinalopening terminating at its lower end in a reduced core receiving`opening forming a shoulder, and a removable sleeve resting on saidshoulder engaging the inner face of said blades, said head having iiuiddischarge passages therein having discharge openings located betweensaid blades.

an inner barrel mounted in said head in ensaid head having a pluralityof Huid discharge passages therein, having outlet openings locatedbetween the cutting blades.

4. For use in combination with a core drill, a cutter head having aplurality of slots at its body having plate-receiving slots, lower lowerend of said head extending there- 3. In a core drill, a cutter head, anouter barrel attached to said cutter head, said head having a pluralityof slots in its lower end extending therethrough, a cutting blade ineach slot, a central longitudinal passage in said head terminating atits lower end in a core receiving opening forming a shoulder in saidpassage, a sleeve seated on said shoulder engaging the inner faces ofsaid blades, and

gagement with the upper end of said sleeve,

head; and a core catcher y blades removably mounted in some of saidslots and extendingoutwardly from said body, said blades having cuttingedges below said rim extending inwardly to the core receiving openingand upper blades removably mounted in others of said slots and extendingoutwardly through said body beyond said lower blades and having cuttingedges above the cutting edges of said lower blades.

6. In a core drill; a cutter head having a fluid receiving recesstherein; sets of cutter `blades removably mounted in said head, one

of said sets havin cutting edges above the cutting edges of the other ofsaid sets; and fluid discharge passages from Said recess having sets ofdischarge outlets one above the other, said upper and lower sets ofdischarge outlets being arranged to flush the cutting edges of saidupper andl lower sets of blades respectively. Y

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 15 day of August, 1927.

FLOYD C. vMERRITT

